(1. 北京科技大学 钢铁冶金新技术国家重点实验室，北京 100083；
2. 北京科技大学 冶金与生态工程学院，北京 100083；
3. 北京科技大学 材料科学与工程学院，北京 100083)
摘 要: 采用高温实验和光学显微镜、扫描电子显微镜等研究Mg含量对1 873 K下Ti-Mg复合脱氧后铸锭样品中夹杂物组成、大小分布以及实验钢中晶内铁素体形核的影响。结果表明：当Mg含量(质量分数)为0.001 5%~0.002 6%时，实验钢中夹杂物的分布最为细小弥散，晶内铁素体形核效果较好。当奥氏体化温度为1 200 ℃时，钢中晶内铁素体的比例较高，有利于晶内铁素体形核的最佳奥氏体晶粒大小为120 μm左右。
关键字: Ti-Mg合金；脱氧；夹杂物；晶内铁素体；奥氏体晶粒
（1. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China;
2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The effects of Mg content on the composition, size distribution of inclusions and microstructure of ingot samples deoxided by Ti-Mg at 1 873 K were investigated by high temperature tests, SEM-EDS and optical microscopy (OM). The results show that when the Mg content (mass fraction) varies from 0.001 5% to 0.002 6%, the inclusions in experimental steel are fine-distributed, and the effectiveness of intragranular ferrite nucleation is better. At austenitizing temperature of 1 200 ℃, the proportion of intragranular ferrite in steel is higher, and the optimized austenite grain size that is beneficial to intragranular ferrite nucleation is about 120 μm.
Key words: Ti-Mg alloy; deoxidation; inclusions; intragranular ferrite; austenite grain
